I'm getting constant brownouts powering ESP32-CAM

[wwilcz]

Hi,

I want to create a solar charged camera, but got stuck half-way. I'm getting a brownout the minute I power WiFi on the ESP32-Cam with the setup from the picture.

The voltages are all ok - 4.1V on the battery, ~3.8V coming out of TP4056, solid 5V out of the boost converter.

The current however is not so ok... ~300mA coming out of the cell, ~280mA coming out of the charger, ~130mA reaching the ESP-Cam from the booster... I can't get it to draw more power.

When I charge the ESP from the USB TTL adapter it draws ~250mA to operate when streaming, so I'm short on current. Funny thing is, when I power the TP4056 from an USB cable with the battery connected (as if I was charging it), the ESP32 runs ok.

I tried adding stacks of capacitors in different connection points to no avail - I'm by no means an expert in electronics; this is actually my second project.

Anyone any ideas what can be done?

[ESP_Sprite]

What specific diode did you add?

[wwilcz]

1N4007. There was no reasoning behind choosing this one. I just had those diodes lying around.

[ESP_Sprite]

That's an 1A diode, which is good, with something like an 0.8'ish volt forward voltage, which is bad because it means your ESP-CAM works at 4.2V... I think an ESP-CAM uses an LM1117 as a LDO, which requires 4.5V before it's in spec, so that may be your issue... easy fix if that is the case would be to tweak the pot on your boostconverter to provide 5.5V or so, or alternatively replace the diode with a Schottky one.

[wwilcz]

Hah, if it were so simple... The brownouts occur regardless of whether I crank up the converter to 6V or remove the diode completely. There isn't even a change in the current with or without the diode - always oscillates between 120-150mA.

[alanesq]

I would try a decent sized capacitor on the 5v feed to the esp32cam
When using wifi it generates large spikes of power draw and this is probably upsetting your step up converter

If you have an oscilloscope it is worth having a look at the 5v feed to the esp32cam to see what is happening

[wwilcz]

I replaced the diode with a 470uF polarized capacitor (biggest I could find). No effect on the current (or anything else) whatsoever.

Is it possible that the boost converter is simply broken?